jonathan? >> the bombings in boston, bill, are partly shocking purely because we are that much safer than we were prior to 9/11. prior to 9/11, the bombings were much more common on american soil. you only need to look back to 1993, of course, and the first bombing of the world trade center. and then in 1995, of course, there was the oklahoma city bombing and many more small scale but deadly bombings in the 1970s. now, a lot of experts say that since the 9/11 attacks our intelligence services and law enforcement have become much better at identifying and preventing any potential attacks. so while we might not feel it right now, staive tis particularly speaking, we are much safer now than we were in the decades before 9/11. bill? >> you know, jonathan, we know at least one of these devices was made using a pressure cooker, perhaps both of them in the end. that is not a new tactic, is it? >> no. it's certainly not. in fact, right here, look at these dates. in 1976, there was a bomb using a pressu